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dea4d055 MW |
1 | ;;; -*-lisp-*- |
2 | ;;; | |
3 | ;;; Protocol for lexical analysis | |
4 | ;;; | |
5 | ;;; (c) 2009 Straylight/Edgeware | |
6 | ;;; | |
7 | ||
8 | ;;;----- Licensing notice --------------------------------------------------- | |
9 | ;;; | |
10 | ;;; This file is part of the Sensble Object Design, an object system for C. | |
11 | ;;; | |
12 | ;;; SOD is free software; you can redistribute it and/or modify | |
13 | ;;; it under the terms of the GNU General Public License as published by | |
14 | ;;; the Free Software Foundation; either version 2 of the License, or | |
15 | ;;; (at your option) any later version. | |
16 | ;;; | |
17 | ;;; SOD is distributed in the hope that it will be useful, | |
18 | ;;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
19 | ;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
20 | ;;; GNU General Public License for more details. | |
21 | ;;; | |
22 | ;;; You should have received a copy of the GNU General Public License | |
23 | ;;; along with SOD; if not, write to the Free Software Foundation, | |
24 | ;;; Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
25 | ||
26 | (cl:in-package #:sod) | |
27 | ||
28 | ;;;-------------------------------------------------------------------------- | |
239fa5bd | 29 | ;;; Class definition. |
dea4d055 | 30 | |
239fa5bd MW |
31 | (export 'sod-token-scanner) |
32 | (defclass sod-token-scanner (token-scanner) | |
33 | ((char-scanner :initarg :char-scanner :reader token-scanner-char-scanner)) | |
dea4d055 | 34 | (:documentation |
239fa5bd | 35 | "A token scanner for SOD input files. |
dea4d055 | 36 | |
239fa5bd MW |
37 | Not a lot here, apart from a character scanner to read from and the |
38 | standard token scanner infrastructure.")) | |
dea4d055 | 39 | |
dea4d055 | 40 | ;;;-------------------------------------------------------------------------- |
239fa5bd MW |
41 | ;;; Indicators and error messages. |
42 | ||
1d8cc67a MW |
43 | (defvar *indicator-map* (make-hash-table) |
44 | "Hash table mapping indicator objects to human-readable descriptions.") | |
45 | ||
239fa5bd MW |
46 | (export 'define-indicator) |
47 | (defun define-indicator (indicator description) | |
48 | "Associate an INDICATOR with its textual DESCRIPTION. | |
49 | ||
50 | Updates the the `*indicator-map*'." | |
51 | (setf (gethash indicator *indicator-map*) description) | |
52 | indicator) | |
53 | ||
54 | (export 'syntax-error) | |
55 | (defun syntax-error (scanner expected &key (continuep t)) | |
56 | "Signal a (maybe) continuable syntax error." | |
57 | (labels ((show-token (type value) | |
58 | (if (characterp type) | |
59 | (format nil "~/sod::show-char/" type) | |
60 | (case type | |
61 | (:id (format nil "<identifier~@[ `~A'~]>" value)) | |
048d0b2d | 62 | (:int "<integer-literal>") |
239fa5bd MW |
63 | (:string "<string-literal>") |
64 | (:char "<character-literal>") | |
65 | (:eof "<end-of-file>") | |
66 | (:ellipsis "`...'") | |
67 | (t (format nil "<? ~S~@[ ~S~]>" type value))))) | |
68 | (show-expected (thing) | |
69 | (acond ((gethash thing *indicator-map*) it) | |
70 | ((atom thing) (show-token thing nil)) | |
71 | ((eq (car thing) :id) | |
72 | (format nil "`~A'" (cadr thing))) | |
73 | (t (format nil "<? ~S>" thing))))) | |
74 | (funcall (if continuep #'cerror* #'error) | |
75 | "Syntax error: ~ | |
76 | expected ~{~#[<bug>~;~A~;~A or ~A~:;~A, ~]~} ~ | |
77 | but found ~A" | |
78 | (mapcar #'show-expected expected) | |
79 | (show-token (token-type scanner) (token-value scanner))))) | |
80 | ||
81 | (export 'lexer-error) | |
82 | (defun lexer-error (char-scanner expected consumedp) | |
83 | "Signal a continuable lexical error." | |
84 | (cerror* "Lexical error: ~ | |
85 | expected ~{~#[<bug>~;~A~;~A or ~A~;:~A, ~]~} ~ | |
86 | but found ~/sod::show-char/~ | |
87 | ~@[ at ~A~]" | |
88 | (mapcar (lambda (exp) | |
89 | (typecase exp | |
90 | (character (format nil "~/sod::show-char/" exp)) | |
91 | (string (format nil "`~A'" exp)) | |
92 | ((cons (eql :digit) *) (format nil "<radix-~A digit>" | |
93 | (cadr exp))) | |
94 | ((eql :eof) "<end-of-file>") | |
95 | ((eql :any) "<character>") | |
96 | (t (format nil "<? ~S>" exp)))) | |
97 | expected) | |
98 | (and (not (scanner-at-eof-p char-scanner)) | |
99 | (scanner-current-char char-scanner)) | |
100 | (and consumedp (file-location char-scanner)))) | |
dea4d055 | 101 | |
33b5686f | 102 | (export 'skip-until) |
048d0b2d MW |
103 | (defparse skip-until (:context (context token-scanner-context) |
104 | (&key (keep-end nil keep-end-p)) | |
105 | &rest token-types) | |
106 | "Discard tokens until we find one listed in TOKEN-TYPES. | |
107 | ||
108 | If KEEP-END is true then retain the found token for later; otherwise | |
109 | discard it. KEEP-END defaults to true if multiple TOKEN-TYPES are given; | |
110 | otherwise false. If end-of-file is encountered then the indicator list is | |
111 | simply the list of TOKEN-TYPES; otherwise the result is `nil'." | |
112 | `(skip-until ,(parser-scanner context) | |
113 | (list ,@token-types) | |
114 | :keep-end ,(if keep-end-p keep-end | |
115 | (> (length token-types) 1)))) | |
116 | ||
33b5686f | 117 | (export 'error) |
048d0b2d MW |
118 | (defparse error (:context (context token-scanner-context) |
119 | (&key) sub &optional (recover t)) | |
120 | "Try to parse SUB; if it fails then report an error, and parse RECOVER. | |
121 | ||
122 | This is the main way to recover from errors and continue parsing. Even | |
123 | then, it's not especially brilliant. | |
124 | ||
125 | If the SUB parser succeeds then just propagate its result: it's like we | |
126 | were never here. Otherwise, try to recover in a sensible way so we can | |
127 | continue parsing. The details of this recovery are subject to change, but | |
128 | the final action is generally to invoke the RECOVER parser and return its | |
129 | result." | |
130 | `(parse-error-recover ,(parser-scanner context) | |
131 | (parser () ,sub) | |
132 | (parser () ,recover))) | |
133 | ||
dea4d055 | 134 | ;;;-------------------------------------------------------------------------- |
239fa5bd MW |
135 | ;;; Lexical analysis utilities. |
136 | ||
33b5686f | 137 | (export 'scan-comment) |
239fa5bd MW |
138 | (defun scan-comment (char-scanner) |
139 | "Scan a comment (either `/* ... */' or `// ...') from CHAR-SCANNER. | |
140 | ||
141 | The result isn't interesting." | |
142 | (with-parser-context (character-scanner-context :scanner char-scanner) | |
143 | (parse (or (and "/*" | |
144 | (and (skip-many () | |
145 | (and (skip-many () (not #\*)) | |
146 | (label "*/" (skip-many (:min 1) #\*))) | |
147 | (not #\/)) | |
148 | #\/)) | |
149 | (and "//" | |
150 | (skip-many () (not #\newline)) | |
151 | (? #\newline)))))) | |
dea4d055 MW |
152 | |
153 | ;;;----- That's all, folks -------------------------------------------------- |